Work disrupted due to lockdown, now I don't think my client is going to pay.

Just before lockdown I agreed with a client to produce some floor plans. This meant surveying the site, taking measurements and creating a digital floor plan which I would send to them. I attended the site before lockdown but because of restrictions couldn’t complete measurements of all areas. We agreed that I would return at a later point to finish measurements. Then lockdown happened and I have not been able to return to site. At the start of lockdown they asked for floorplans on what I had done so far and said I would complete the project at a later date when possible.